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"The Power of Movement in Plants"

They were subjected to a rather
varying temperature, generally between 52o and 58o F. A few cases have not
been thought worth recording, in which the whole tip was blackened, or in
which the seedling soon became unhealthy.
(1.) The radicle was slightly deflected from the cauterised side in one day
(i.e. 24 h.); in three days it stood at 60o from the perpendicular; in four
days at 90o; on the fifth day it was curved up about 40o above the horizon;
so that it had passed through an angle of 130o in the five days, and this
was the greatest amount of curvature observed.
(2.) In two days radicle slightly deflected; after seven days
[page 173]
deflected 69o from the perpendicular and from the cauterised side; after
eight days the angle amounted to nearly 90o.
(3.) After one day slight deflection, but the cauterised mark was so faint
that the same side was again touched with caustic. In four days from the
first touch deflection amounted to 78o, which in an additional day
increased to 90o.
(4.) After two days slight deflection, which during the next three days
certainly increased but never became great; the radicle did not grow well
and died on the eighth day.


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